Mask vent with side wall

ABSTRACT

A vent arrangement for a mask system includes a mask component and a mask vent provided to the mask component. The mask vent includes a plurality of vent holes each extending through a thickness of the mask component and each including a vent exit, and a continuous side wall structured to surround the plurality of vent exits of the vent holes.

1 CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of Ser. No. 15/023,917, filed Mar.22, 2016, which is the U.S. national phase of International ApplicationNo. PCT/AU2014/050257 filed 30 Sep. 2014, which designated the U.S. andclaims priority to AU Patent Application No. 2013903819 filed 3 Oct.2013, the entire contents of each of which are hereby incorporated byreference.

2 STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT

Not Applicable

3 THE NAMES OF PARTIES TO A JOINT RESEARCH DEVELOPMENT

Not Applicable

4 SEQUENCE LISTING

Not Applicable

5 BACKGROUND OF THE INVENTION

5.1 Field of the Invention

The present technology relates to one or more of the diagnosis,treatment, prevention, and amelioration of respiratory disorders. Inparticular, the present technology relates to medical devices, and theiruse for treating respiratory disorders and for preventing respiratorydisorders.

5.2 Description of the Related Art

The respiratory system of the body facilitates gas exchange. The noseand mouth form the entrance to the airways of a patient.

The airways include a series of branching tubes, which become narrower,shorter and more numerous as they penetrate deeper into the lung. Theprime function of the lung is gas exchange, allowing oxygen to move fromthe air into the venous blood and carbon dioxide to move out. Thetrachea divides into right and left main bronchi, which further divideeventually into terminal bronchioles. The bronchi make up the conductingairways, and do not take part in gas exchange. Further divisions of theairways lead to the respiratory bronchioles, and eventually to thealveoli. The alveolated region of the lung is where the gas exchangetakes place, and is referred to as the respiratory zone. See West,Respiratory Physiology—the Essentials.

A range of respiratory disorders exist.

Obstructive Sleep Apnea (OSA), a form of Sleep Disordered Breathing(SDB), is characterized by occlusion or obstruction of the upper airpassage during sleep. It results from a combination of an abnormallysmall upper airway and the normal loss of muscle tone in the region ofthe tongue, soft palate and posterior oropharyngeal wall during sleep.The condition causes the affected patient to stop breathing for periodstypically of 30 to 120 seconds duration, sometimes 200 to 300 times pernight. It often causes excessive daytime somnolence, and it may causecardiovascular disease and brain damage. The syndrome is a commondisorder, particularly in middle aged overweight males, although aperson affected may have no awareness of the problem. See U.S. Pat. No.4,944,310 (Sullivan).

Cheyne-Stokes Respiration (CSR) is a disorder of a patient's respiratorycontroller in which there are rhythmic alternating periods of waxing andwaning ventilation during sleep, causing repetitive de-oxygenation andre-oxygenation of the arterial blood. It is possible that CSR is harmfulbecause of the repetitive hypoxia. In some patients CSR is associatedwith repetitive arousal from sleep, which causes severe sleepdisruption, increased sympathetic activity, and increased afterload. SeeU.S. Pat. No. 6,532,959 (Berthon-Jones).

Obesity Hyperventilation Syndrome (OHS) is defined as the combination ofsevere obesity and awake chronic hypercapnia, in the absence of otherknown causes for hypoventilation. Symptoms include dyspnea, morningheadache and excessive daytime sleepiness.

Chronic Obstructive Pulmonary Disease (COPD) encompasses any of a groupof lower airway diseases that have certain characteristics in common.These include increased resistance to air movement, extended expiratoryphase of respiration, and loss of the normal elasticity of the lung.Examples of COPD are emphysema and chronic bronchitis. COPD is caused bychronic tobacco smoking (primary risk factor), occupational exposures,air pollution and genetic factors. Symptoms include: dyspnea onexertion, chronic cough and sputum production.

Neuromuscular Disease (NMD) is a broad term that encompasses manydiseases and ailments that impair the functioning of the muscles eitherdirectly via intrinsic muscle pathology, or indirectly via nervepathology. Some NMD patients are characterised by progressive muscularimpairment leading to loss of ambulation, being wheelchair-bound,swallowing difficulties, respiratory muscle weakness and, eventually,death from respiratory failure. Neuromuscular disorders can be dividedinto rapidly progressive and slowly progressive: (i) Rapidly progressivedisorders: Characterised by muscle impairment that worsens over monthsand results in death within a few years (e.g. Amyotrophic lateralsclerosis (ALS) and Duchenne muscular dystrophy (DMD) in teenagers);(ii) Variable or slowly progressive disorders: Characterised by muscleimpairment that worsens over years and only mildly reduces lifeexpectancy (e.g. Limb girdle, Facioscapulohumeral and Myotonic musculardystrophy). Symptoms of respiratory failure in NMD include: increasinggeneralised weakness, dysphagia, dyspnea on exertion and at rest,fatigue, sleepiness, morning headache, and difficulties withconcentration and mood changes.

Chest wall disorders are a group of thoracic deformities that result ininefficient coupling between the respiratory muscles and the thoraciccage. The disorders are usually characterised by a restrictive defectand share the potential of long term hypercapnic respiratory failure.Scoliosis and/or kyphoscoliosis may cause severe respiratory failure.Symptoms of respiratory failure include: dyspnea on exertion, peripheraloedema, orthopnea, repeated chest infections, morning headaches,fatigue, poor sleep quality and loss of appetite.

Otherwise healthy individuals may take advantage of systems and devicesto prevent respiratory disorders from arising.

5.2.1 Systems

One known product used for treating sleep disordered breathing is the S9Sleep Therapy System, manufactured by ResMed.

5.2.2 Therapy

Nasal Continuous Positive Airway Pressure (CPAP) therapy has been usedto treat Obstructive Sleep Apnea (OSA). The hypothesis is thatcontinuous positive airway pressure acts as a pneumatic splint and mayprevent upper airway occlusion by pushing the soft palate and tongueforward and away from the posterior oropharyngeal wall.

Non-invasive ventilation (NIV) has been used to treat OHS, COPD, MD andChest Wall disorders.

5.2.3 Patient Interface

The application of a supply of air at positive pressure to the entranceof the airways of a patient is facilitated by the use of a patientinterface, such as a nasal mask, full-face mask or nasal pillows. Arange of patient interface devices are known, however a number of themsuffer from being one or more of obtrusive, aesthetically undesirable,poorly fitting, difficult to use, and uncomfortable especially when wornfor long periods of time or when a patient is unfamiliar with a system.Masks designed solely for aviators as part of personal protectionequipment or for the administration of anaesthetics may be tolerable fortheir original application, but nevertheless be undesirablyuncomfortable to be worn for extended periods, for example, whilesleeping.

5.2.3.1 Seal-Forming Portion

Patient interfaces typically include a seal-forming portion.

One type of seal-forming portion extends around the periphery of thepatient interface, and is intended to seal against the user's face whenforce is applied to the patient interface with the seal-forming portionin confronting engagement with the user's face. The seal-forming portionmay include an air or fluid filled cushion, or a moulded or formedsurface of a resilient seal element made of an elastomer such as arubber. With this type of seal-forming portion, if the fit is notadequate, there will be gaps between the seal-forming portion and theface, and additional force will be required to force the patientinterface against the face in order to achieve a seal.

Another type of seal-forming portion incorporates a flap seal of thinmaterial so positioned about the periphery of the mask so as to providea self-sealing action against the face of the user when positivepressure is applied within the mask. Like the previous style of sealforming portion, if the match between the face and the mask is not good,additional force may be required to effect a seal, or the mask may leak.Furthermore, if the shape of the seal-forming portion does not matchthat of the patient, it may crease or buckle in use, giving rise toleaks.

Another form of seal-forming portion may use adhesive to effect a seal.

Some patients may find it inconvenient to constantly apply and remove anadhesive to their face.

A range of patient interface seal-forming portion technologies aredisclosed in the following patent applications, assigned to ResMedLimited: WO 1998/004,310; WO 2006/074,513; WO 2010/135,785.

5.2.3.2 Positioning and Stabilising

A seal-forming portion of a patient interface used for positive airpressure therapy is subject to the corresponding force of the airpressure to disrupt a seal. Thus a variety of techniques have been usedto position the seal-forming portion, and to maintain it in sealingrelation with the appropriate portion of the face.

One technique is the use of adhesives. See for example US Patentpublication US 2010/0000534.

Another technique is the use of one or more straps and stabilisingharnesses. Many such harnesses suffer from being one or more ofill-fitting, bulky, uncomfortable and awkward to use.

5.2.3.3 Vent Technologies

Some forms of patient interface systems may include a vent to allow thewashout of exhaled carbon dioxide. Many such vents are noisy. Others mayblock in use and provide insufficient washout. Some vents may bedisruptive of the sleep of a bed-partner 1100 of the patient 1000, e.g.through noise or focussed airflow.

ResMed Limited has developed a number of improved mask venttechnologies. See WO 1998/034,665; WO 2000/078,381; U.S. Pat. No.6,581,594; US Patent Application; US 2009/0050156; US Patent Application2009/0044808.

Table of noise of prior masks (ISO 17510-2:2007, 10 cmH₂O pressure at 1metre):

A-weighted A-weighted sound power sound pressure level dbA dbA Year Maskname Mask type (uncertainty) (uncertainty) (approx.) Glue-on (*) nasal50.9 42.9 1981 ResCare nasal 31.5 23.5 1993 standard (*) ResMed nasal29.5 21.5 1998 Mirage (*) ResMed nasal 36 (3) 28 (3) 2000 UltraMirageResMed nasal 32 (3) 24 (3) 2002 Mirage Activa ResMed nasal 30 (3) 22 (3)2008 Mirage Micro ResMed nasal 29 (3) 22 (3) 2008 Mirage SoftGel ResMednasal 26 (3) 18 (3) 2010 Mirage FX ResMed nasal 37 29 2004 Mirage Swift(*) pillows ResMed nasal 28 (3) 20 (3) 2005 Mirage Swift II pillowsResMed nasal 25 (3) 17 (3) 2008 Mirage Swift LT pillows (*) one specimenonly, measured using test method specified in ISO3744 in CPAP mode at 10cmH₂O)

Sound pressure values of a variety of objects are listed below:

A-weighted sound pressure dbA Object (uncertainty) Notes Vacuum cleaner:Nilfisk 68 ISO3744 at Walter Broadly Litter Hog: B+ 1 m distance GradeConversational speech 60 1 m distance Average home 50 Quiet library 40Quiet bedroom at night 30 Background in TV studio 205.2.3.4 Nasal Pillow Technologies

One form of nasal pillow is found in the Adam Circuit manufactured byPuritan Bennett. Another nasal pillow, or nasal puff is the subject ofU.S. Pat. No. 4,782,832 (Trimble et al.), assigned to Puritan-BennettCorporation.

ResMed Limited has manufactured the following products that incorporatenasal pillows: SWIFT nasal pillows mask, SWIFT II nasal pillows mask,SWIFT LT nasal pillows mask, SWIFT FX nasal pillows mask and LIBERTYfull-face mask. The following patent applications, assigned to ResMedLimited, describe nasal pillows masks: International Patent ApplicationWO2004/073,778 (describing amongst other things aspects of ResMed SWIFTnasal pillows), US Patent Application 2009/0044808 (describing amongstother things aspects of ResMed SWIFT LT nasal pillows); InternationalPatent Applications WO 2005/063,328 and WO 2006/130,903 (describingamongst other things aspects of ResMed LIBERTY full-face mask);International Patent Application WO 2009/052,560 (describing amongstother things aspects of ResMed SWIFT FX nasal pillows).

5.2.4 PAP Device

The air at positive pressure is typically supplied to the airway of apatient by a PAP device such as a motor-driven blower. The outlet of theblower is connected via a flexible delivery conduit to a patientinterface as described above.

5.2.5 Mandibular Repositioning

A mandibular repositioning device (MRD) is one of the treatment optionsfor sleep apnea. It is a custom made, adjustable oral applianceavailable from a dentist that holds the lower jaw in a forward positionduring sleep. This mechanical protrusion expands the space behind thetongue, puts tension on the pharyngeal walls to reduce collapse of theairway and diminishes palate vibration.

6 BRIEF SUMMARY OF THE TECHNOLOGY

The present technology is directed towards providing medical devicesused in the diagnosis, amelioration, treatment, or prevention ofrespiratory disorders having one or more of improved comfort, cost,efficacy, ease of use and manufacturability.

A first aspect of the present technology relates to apparatus used inthe diagnosis, amelioration, treatment or prevention of a respiratorydisorder.

Another aspect of the present technology relates to methods used in thediagnosis, amelioration, treatment or prevention of a respiratorydisorder.

Another aspect of the present technology relates to a gas washout ventfor a mask system structured to disperse or diffuse the exhaust ventflow, e.g., to reduce air jetting and noise.

Another aspect of the present technology relates to a gas washout ventincluding a side wall or hood at least partly surrounding one or morevent holes to disperse or diffuse the exhaust vent flow.

Another aspect of the present technology relates to a vent arrangementfor a mask system including a mask component and a mask vent provided tothe mask component. The mask vent includes a plurality of vent holeseach extending through a thickness of the mask component and eachincluding a vent exit, and a continuous side wall structured to surroundthe plurality of vent exits of the vent holes.

Of course, portions of the aspects may form sub-aspects of the presenttechnology. Also, various ones of the sub-aspects and/or aspects may becombined in various manners and also constitute additional aspects orsub-aspects of the present technology.

Other features of the technology will be apparent from consideration ofthe information contained in the following detailed description,abstract, drawings and claims.

7 BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS

The present technology is illustrated by way of example, and not by wayof limitation, in the figures of the accompanying drawings, in whichlike reference numerals refer to similar elements including:

7.1 Treatment Systems

FIG. 1a shows a system in accordance with the present technology. Apatient 1000 wearing a patient interface 3000, receives a supply of airat positive pressure from a PAP device 4000. Air from the PAP device ishumidified in a humidifier 5000, and passes along an air circuit 4170 tothe patient 1000.

FIG. 1b shows a PAP device 4000 in use on a patient 1000 with a nasalmask 3000.

FIG. 1c shows a PAP device 4000 in use on a patient 1000 with afull-face mask 3000.

7.2 Therapy

7.2.1 Respiratory System

FIG. 2a shows an overview of a human respiratory system including thenasal and oral cavities, the larynx, vocal folds, oesophagus, trachea,bronchus, lung, alveolar sacs, heart and diaphragm.

FIG. 2b shows a view of a human upper airway including the nasal cavity,nasal bone, lateral nasal cartilage, greater alar cartilage, nostril,lip superior, lip inferior, larynx, hard palate, soft palate,oropharynx, tongue, epiglottis, vocal folds, oesophagus and trachea.

7.2.2 Facial Anatomy

FIG. 2c is a front view of a face with several features of surfaceanatomy identified including the lip superior, upper vermillion, lowervermillion, lip inferior, mouth width, endocanthion, a nasal ala,nasolabial sulcus and cheilion.

FIG. 2d is a side view of a head with several features of surfaceanatomy identified including glabella, sellion, pronasale, subnasale,lip superior, lip inferior, supramenton, nasal ridge, otobasion superiorand otobasion inferior. Also indicated are the directions superior &inferior, and anterior & posterior.

FIG. 2e is a further side view of a head. The approximate locations ofthe

Frankfort horizontal and nasolabial angle are indicated.

FIG. 2f shows a base view of a nose.

FIG. 2g shows a side view of the superficial features of a nose.

FIG. 2h shows subcutaneal structures of the nose, including lateralcartilage, septum cartilage, greater alar cartilage, lesser alarcartilage and fibrofatty tissue.

FIG. 2i shows a medial dissection of a nose, approximately severalmillimeters from a sagittal plane, amongst other things showing theseptum cartilage and medial crus of greater alar cartilage.

FIG. 2j shows a front view of the bones of a skull including thefrontal, temporal, nasal and zygomatic bones. Nasal concha areindicated, as are the maxilla, mandible and mental protuberance.

FIG. 2k shows a lateral view of a skull with the outline of the surfaceof a head, as well as several muscles. The following bones are shown:frontal, sphenoid, nasal, zygomatic, maxilla, mandible, parietal,temporal and occipital. The mental protuberance is indicated. Thefollowing muscles are shown: digastricus, masseter sternocleidomastoidand trapezius.

FIG. 21 shows an anterolateral view of a nose.

7.3 Patient Interface

FIG. 3-1 shows mask system including a mask vent according to an exampleof the present technology.

FIG. 3-2 shows a mask vent according to an example of the presenttechnology.

FIG. 3-3 shows a mask vent according to an example of the presenttechnology.

FIG. 3-4 shows a mask vent according to an example of the presenttechnology.

FIGS. 3-5-1 to 3-5-7 show various views of an elbow assembly including amask vent according to an example of the present technology.

FIGS. 3-6-1 to 3-6-2 show various views of an elbow assembly including amask vent according to an example of the present technology.

FIGS. 3-6-3 to 3-6-9 show various views of the mask vent of FIGS. 3-6-1to 3-6-2 removed from the elbow assembly.

FIGS. 3-7-1 to 3-7-5 show a mask system including the elbow assembly of

FIGS. 3-6-1 to 3-6-2 according to an example of the present technology.

FIGS. 3-8-1 to 3-8-2 show various views of an elbow assembly including amask vent according to an example of the present technology.

FIGS. 3-9-1 to 3-9-2 show various views of an elbow assembly including amask vent according to an example of the present technology.

FIGS. 3-10-1 to 3-10-2 show various views of an elbow assembly includinga mask vent according to an example of the present technology.

FIGS. 3-11-1 to 3-11-2 show various views of an elbow assembly includinga mask vent according to an example of the present technology.

FIGS. 3-12-1 to 3-12-2 show various views of an elbow assembly includinga mask vent according to an example of the present technology.

FIGS. 3-13-1 to 3-13-2 show various views of an elbow assembly includinga mask vent according to an example of the present technology.

7.4 Pap Device

FIG. 4a shows a PAP device in accordance with one form of the presenttechnology.

8 DETAILED DESCRIPTION OF EXAMPLES OF THE TECHNOLOGY

Before the present technology is described in further detail, it is tobe understood that the technology is not limited to the particularexamples described herein, which may vary. It is also to be understoodthat the terminology used in this disclosure is for the purpose ofdescribing only the particular examples discussed herein, and is notintended to be limiting.

8.1 Treatment Systems

In one form, the present technology comprises apparatus for treating arespiratory disorder. The apparatus may comprise a PAP device 4000 forsupplying pressurised respiratory gas, such as air, to the patient 1000via an air delivery tube leading to a patient interface 3000.

8.2 Therapy

In one form, the present technology comprises a method for treating arespiratory disorder comprising the step of applying positive pressureto the entrance of the airways of a patient 1000.

8.2.1 Nasal CPAP for OSA

In one form, the present technology comprises a method of treatingObstructive Sleep Apnea in a patient by applying nasal continuouspositive airway pressure to the patient.

In certain embodiments of the present technology, a supply of air atpositive pressure is provided to the nasal passages of the patient viaone or both nares.

In certain embodiments of the present technology, mouth breathing islimited, restricted or prevented.

8.3 Patient Interface 3000

A non-invasive patient interface 3000 in accordance with one aspect ofthe present technology comprises the following functional aspects: aseal-forming structure 3100, a plenum chamber 3200, a positioning andstabilising structure (e.g., headgear), and a connection port 3600 forconnection to air circuit, e.g., see FIG. 3-7-5 for example. In someforms a functional aspect may be provided by one or more physicalcomponents. In some forms, one physical component may provide one ormore functional aspects. In use the seal-forming structure 3100 isarranged to surround an entrance to the airways of the patient so as tofacilitate the supply of air at positive pressure to the airways.

8.3.1 Seal-Forming Structure 3100

In one form of the present technology, a seal-forming structure 3100provides a sealing-forming surface, and may additionally provide acushioning function.

A seal-forming structure 3100 in accordance with the present technologymay be constructed from a soft, flexible, resilient material such assilicone.

In one form, the seal-forming structure 3100 comprises a sealing flange3110 and a support flange 3120, e.g., see FIG. 3-7-5 for example. In anexample, the sealing flange 3110 comprises a relatively thin member witha thickness of less than about 1 mm, for example about 0.25 mm to about0.45 mm, that extends around the perimeter of the plenum chamber 3200.Support flange 3120 may be relatively thicker than the sealing flange3110. The support flange 3120 is disposed between the sealing flange3110 and the marginal edge of the plenum chamber 3200, and extends atleast part of the way around the perimeter. The support flange 3120 isor includes a spring-like element and functions to support the sealingflange 3110 from buckling in use. In use the sealing flange 3110 canreadily respond to system pressure in the plenum chamber 3200 acting onits underside to urge it into tight sealing engagement with the face.

In another form the seal-forming portion of the non-invasive patientinterface 3000 comprises a pair of nasal puffs, or nasal pillows, eachnasal puff or nasal pillow being constructed and arranged to form a sealwith a respective naris of the nose of a patient.

Nasal pillows in accordance with an aspect of the present technologyinclude: a frusto-cone, at least a portion of which forms a seal on anunderside of the patient's nose; a stalk; and a flexible region on theunderside of the frusto-cone connecting the cone to the stalk. Inaddition, the structure to which the nasal pillow of the presenttechnology is connected includes a flexible region adjacent the base ofthe stalk. The flexible regions can act in concert to facilitate auniversal joint structure that is accommodating of relativemovement-both displacement and angular—of the frusto-cone and thestructure to which the nasal pillow is connected. For example, thefrusto-cone may be axially displaced towards the structure to which thestalk is connected.

In one form the non-invasive patient interface 3000 comprises aseal-forming portion that forms a seal in use on an upper lip region(that is, the lip superior) of the patient's face.

In one form the non-invasive patient interface 3000 comprises aseal-forming portion that forms a seal in use on a chin-region of thepatient's face.

8.3.2 Plenum Chamber 3200

The plenum chamber 3200 may have a perimeter that is shaped to becomplementary to the surface contour of the face of an average person inthe region where a seal will form in use. In use, a marginal edge of theplenum chamber 3200 is positioned in close proximity to an adjacentsurface of the face. Actual contact with the face is provided by theseal-forming structure 3100. The seal-forming structure 3100 may extendin use about the entire perimeter of the plenum chamber 3200.

8.3.3 Positioning and Stabilising Structure

The seal-forming structure 3100 of the patient interface 3000 of thepresent technology may be held in sealing position in use by thepositioning and stabilising structure.

8.3.4 Vent 3400

In one form, the patient interface 3000 may include a vent 3400constructed and arranged to allow for the washout of exhaled carbondioxide, e.g., see FIG. 3-7-5.

One form of vent 3400 in accordance with the present technologycomprises a plurality of holes, for example, about 2 to about 40 holes,about 5 to about 20 holes, about 20 to about 80 holes, about 40 to about60 holes, or about 45 to about 55 holes. In an alternativeimplementation, the vent 3400 can comprise a woven mesh structurecomprising numerous microscopic holes.

The vent 3400 may be located in the plenum chamber. Alternatively, thevent may be located in a decoupling structure, e.g. a swivel.

FIG. 3-1 shows a patient interface in accordance with one form of thepresent technology including a mask system or mask 100 including a rigidor semi-rigid portion 110 (often referred to as a shell or frame) and asoft, patient contacting portion 120 adapted to form a seal with thepatient's nose and/or mouth (often referred to as the seal formingstructure, cushion, or nasal prong arrangement). An elbow assembly maybe provided to the frame and adapted to be connected to an air deliverytube that delivers breathable gas to the patient. However, it should beappreciated that other mask arrangements are possible, e.g., not rigid(e.g., constructed of cloth).

One or more gas washout vents or vent arrangements 140 are provided tothe mask or associated conduit to discharge exhaled gas from the mask toatmosphere. In examples, the one or more vents may be provided to a maskcomponent of the mask, i.e., to the frame and/or to the elbow assemblyof the mask. One or more vents in the associated conduit are alsopossible.

It should be appreciated that each vent may be adapted for use with anysuitable interface type, e.g., nasal masks, full-face masks, nose andmouth masks, nasal prongs, pillows, nozzles, cannulae, etc.

The vent arrangements in accordance with examples of the presenttechnology are structured to disperse or diffuse the exhaust vent flow.Increased dispersion or diffusion of exhaust vent flow reducesdisturbing or unfavourable effects of vent airflow, e.g., air jettingonto bed clothes/pillows and bed partners, noise.

In examples, one or more side walls are provided around the washoutvents or holes to surround or enclose the vent outlet or vent exit ofthe vent holes and reduce the unfavourable effects of vent airflow.

In an example, venting flow at 12 cmH₂O pressure is about 40 L/m, andair velocity at each vent opening is about 45 m/s about (162 km/h). Suchhigh velocity vent airflow will cause vent airflow from all the adjacentvent holes to converge with one another and pull in additional airsurrounding the venting area into the converged stream due to theVenturi effect. The amount of air pulled into the converged stream canbe more than 10 times larger than the original flow in some examples. Toprevent or at least reduce additional air from being pulled into thevent airflow, a side wall is provided around the venting area accordingto examples of the present technology.

In an example, the side wall reduces negative pressure along the surfaceadjacent the vent outlet which reduces air being pulled into the ventstream. This allows greater dispersion or diffusion of the vent airflowadjacent the vent outlet and at least reduces convergence of the airstream to reduce air velocity downstream from the vent outlet. In anexample, the air velocity downstream from the venting area (e.g., about300 mm downstream from the venting area) provided with a side wall maybe at least ½ or less (e.g., ⅓) of the air velocity downstream from theventing area with no side wall. As a result, venting noise (e.g., soundpower (dB)) is reduced, as is disruption to any bed-partner 1100 of thepatient 1000. In effect, the venting flow has been spread over a widerarea, achieving a more even or uniform flow profile across the walledarea, thereby decreasing its velocity. The amount of reduction ofdownstream air velocity increases with the height of the side wall up tothe limit which is reached with uniform flow.

The greater the density of vent holes, the smaller the holes may be madewhile maintaining the same venting flow rate. It may be shown that agreater density of smaller holes improves the amount of diffusion forthe same height of surrounding side wall. In other words, as the densityof vent holes increases, the side wall height may be reduced whilepreserving the same reduction in downstream air velocity at a givendistance from the vent. In one example, 36 tapered vent holes of 0.75 mmdiameter are disposed on a uniform hexagonal grid with inter-holespacing of 2.5 mm. In this example, the side wall height is 10 mm.

In an example, as shown in FIG. 3-1, the mask vent 140 is provided tothe mask frame 110 of the mask system 100. In the illustrated example,the mask system includes the mask frame 110, the cushion 120 provided tothe frame and adapted to form a seal with the patient's nose and mouth,and a shroud 130 provided to the frame and structured to attach headgearto the mask system. The lower portion of the frame includes an opening112 adapted to receive or otherwise communicate with an elbow assembly,and the upper portion of the frame includes the mask vent 140 for gaswashout. As illustrated, the bottom end of the shroud 130 includes anopening 132 to accommodate the elbow assembly and the top end of theshroud 130 includes an opening 134 to accommodate the mask vent 140.Further examples and details of such mask system are disclosed inInternational Publication No. WO 2009/108995, which is incorporatedherein by reference in its entirety. However, it should be appreciatedthat the mask vent 140 may be adapted for use with other suitableinterface types.

As illustrated, the mask vent 140 includes a venting area 141 having aplurality of vent holes 142. Each vent hole extends through a thicknessof the mask frame and each includes a vent exit. The mask vent 140includes a continuous side wall 150 provided to the mask framestructured to surround the plurality of vent exits of the vent holes142. In an alternative example, the side wall may at least partlysurround one or more of the vent holes.

The term “side wall” should be understood to include not only structuresthat project outwards from the mask component, such as the side wall150, but also structures that project inwards from the mask component,such as a wall surrounding a recess in the mask component. In an exampleof such a configuration, as described below, the mask vent may berecessed within an interior of the mask, i.e., the side wall of the ventsupports the venting area within an interior of the mask.

In an alternative example, the side wall may include a hood to at leastpartly surround or enclose one or more of the vent holes.

In the illustrated example, the side wall 150 extends in the directionof the vent airflow (e.g., perpendicular to the exterior surface 115 ofthe mask frame 110 and/or perpendicular to a longitudinal axis of eachvent hole 142). In alternative examples, the side wall may be angledwith respect to the exterior surface of the mask frame and/or thelongitudinal axis of each vent hole.

In the illustrated example, the side wall 150 includes a uniform orconstant height along its perimeter, e.g., side wall includessubstantially the same height from its connection to the frame to itsfree end. However, in an alternative example, the side wall may includeone or more portions with different heights along its perimeter.

In the illustrated example, the side wall 150 includes a uniform orconstant thickness along its entire perimeter and from its connection tothe frame to its free end. However, in an alternative example, thethickness of the side wall may be tapered along its height, e.g.,tapered from its connection to the frame to its free end. Also, in analternative example, the side wall may include different thicknessesalong its perimeter.

In the illustrated example, the vent holes 142 are arranged in columns,e.g., to allow more holes to be fitted into a smaller space. Asillustrated, the vent arrangement includes a center column includingfive holes which is flanked by inner intermediate columns each includingfive holes which is flanked by outer intermediate columns each includingfour holes which is flanked by outside columns each including fourholes. The holes in the outside columns are aligned with holes in theinner intermediate columns, which are offset from holes in the centercolumn and outer intermediate column, forming a hexagonal gridarrangement. It should be appreciated that each column may include anysuitable number of holes, and the columns may be arranged in othersuitable manners with respect to one another.

In the illustrated example, the vent holes 142 are arranged to provide aventing area 141 with a generally oblong, ovoid, or oval shape. Asillustrated, the side wall 150 is continuous and is structured tosurround the entire venting area 141, e.g., side wall includes generallysimilar shape to the venting area, e.g., generally oblong, ovoid, oroval shaped side wall. However, in alternative examples, the side wallmay include a different shape than the venting area. Also, the side wallmay be structured to only surround one or more portions of the ventingarea. In addition, it should be appreciated that the venting area andside wall may have other suitable shapes, e.g., depending on maskconfiguration, venting requirements, etc.

For example, FIGS. 3-2 to 3-4 illustrate alternative side wallarrangements.

In FIG. 3-2, the side wall 250 includes a hexagonal shape that surroundsthe venting area 241 with vent holes 242. In FIG. 3-3, the side wall 350includes a circular shape that surrounds the venting area 341 with ventholes 342. In FIG. 3-4, the side wall 450 includes a circular shape thatsurrounds the venting area 441 with vent holes 442, and a plurality oftruncated interior walls or ribs 445 are provided within the side wall450 and extend at least partially through the venting area 441. Asillustrated, the interior walls are arranged in a radial manner from anaxis of the circular side wall. However, it should be appreciated thatthe interior walls or ribs may have other suitable shapes, e.g., arcuateor non-linear shape, and may be arranged within the venting area inother suitable manners.

Each vent hole may have a generally part conic shape, including opposedwalls that converge from a larger diameter to a smaller diameter, asviewed in the direction of exhausted gas. Alternatively, each vent holemay have a generally cylindrical shape with a substantially constantdiameter along its length.

In an alternative example, the mask vent may be provided to the elbowassembly of the mask system. For example, the mask vent may beintegrated or integrally formed in one piece with the elbow assembly.Alternatively, the mask vent may be retrofit to an existing elbowassembly, e.g., replace an original or existing mask vent on an elbowassembly.

For example, FIGS. 3-5-1 to 3-5-7 show the mask vent 540 integrallyformed (e.g., molded) in one piece with the elbow assembly 580. Thearrangement provides a single piece elbow assembly with removable parts.

As illustrated, the elbow assembly 580 includes a first end 581structured to releasably engage with an opening in a mask frame and asecond end 582 structured to releasably engage with an air deliverytube. In the illustrated example, the first end 581 includes a flexiblequick release mechanism including a T-shaped collar 583 structured toreleasably engage a flange surrounding the opening in the mask framewith a snap-fit. Further examples and details of such quick releasemechanism are disclosed in U.S. Pat. No. 6,907,882, which isincorporated herein by reference in its entirety. However, it should beappreciated that the elbow assembly may be connected or otherwisecommunicated with the opening in the mask frame in other suitablemanners.

A baffle 584 is provided within the interior portion of the elbowassembly and separates the intake port 590 and the exhaust port 592,e.g., see FIGS. 3-5-6 and 3-5-7. The mask vent 540 is provided at theoutlet of the exhaust port 592. In this manner, exhalation gases from aninterior of the mask can flow through exhaust port 592 of the elbowassembly 580, through the mask vent 540, and to the atmosphere.

As illustrated, the mask vent 540 includes an inlet portion 544 toreceive gas from the outlet of the exhaust port 592 of the elbowassembly, a vent portion 546 including the plurality of vent holes 542,and an outlet portion 548 to receive gas from the outlets of the ventholes 542. In the example, the inlet portion 544 includes an arcuate orotherwise angled side wall 545 to guide exhaust gas from the outlettowards the vent and outlet portions. In the illustrated example, asbest shown in FIG. 3-5-7, the axes of the vent holes 542 and alongitudinal axis a1 of the outlet portion 548 are oriented to directexhaust gas in a direction that is slightly offset or possibly parallelto a longitudinal axis a2 of the second end 582 of the elbow assembly(e.g., axes oriented about 0-45° from the axis of the second end), e.g.,to ensure gas is vented in a direction away from the mask system and thepatient. In the example, the outlet portion 548 provides a continuous,side wall 550 around the vent portion and vent holes thereof to enhancedispersion or diffusion of exhaust vent flow as described above.

In the illustrated example, the vent holes 542 are provided through aninterior wall 549 of the mask vent 540 and arranged in columns of fivevent holes, and the side wall 550 includes a generally rectangular shapethat surrounds the vent holes and extends in the direction of the ventairflow. However, as noted above, it should be appreciated that the ventholes and side wall may have other suitable arrangements.

FIGS. 3-6-1 to 3-6-9 show an elbow assembly 680 and mask vent 640according to another example of the present technology. In contrast tothe example shown in FIGS. 3-5-1 to 3-5-7, the mask vent 640 is providedas a vent cap that is formed separately from the elbow assembly 680 andattached thereto. In an example, the vent cap may be retrofit to anexisting elbow assembly, e.g., vent cap replaces elastomeric vent coveron elbow assembly disclosed in U.S. Pat. No. 6,907,882 for example.

As illustrated in FIG. 3-6-2, the elbow assembly 680 includes a flange686 provided at a distal end of an annular wall 687 surrounding theoutlet of the exhaust port 692. The vent cap 640 is structured toreleasably engage the flange 686, e.g., with a snap-fit, to connect thevent cap 640 to the elbow assembly 680. Remaining aspects of the elbowassembly 680, e.g., first end 681 with flexible quick release mechanism,second end 682, baffle 684 separating intake port 690 and exhaust port692 is similar to elbow assembly 580 described above.

The vent cap 640 includes a main body 643 providing an inlet portion 644with arcuate or angled side wall 645 to guide exhaust gas from theoutlet of the elbow assembly towards the vent, a vent portion 646including interior wall 649 with the plurality of vent holes 642, and anoutlet portion 648 including side wall 650 to diffuse vent flow asdescribed above.

A support wall 647 is provided to the inlet portion 644 along its inletopening. As illustrated, the support wall 647 includes a non-continuousstructure, e.g., first and second wall portions 647.1 and 647.2, e.g.,see FIGS. 3-6-3 and 3-6-6. However, it should be appreciated that thesupport wall may have other suitable structures, e.g., continuous wallstructure.

An engagement or seal ring 660, e.g., constructed of a more flexiblematerial than the main body 643, is provided to the support wall 647.The engagement ring 660 includes grooves 661 through its thickness thatare adapted to receive respective wall portions 647.1 and 647.2 of thesupport wall 647 (e.g., see FIGS. 3-6-2, 3-6-3, 3-6-6, and 3-6-9) so asto attach the engagement ring to the support wall. The engagement ring660 may be formed separately and attached to the support wall 647, orthe engagement ring 660 may be integrally formed along with the mainbody 643 and support wall thereof, e.g., co-molded.

As best shown in FIG. 3-6-9, the engagement ring 660 includes an annulargroove 662 along its inside surface. The inside surface may be ramped ortapered along it entry opening 664 to facilitate engagement andalignment of the engagement ring with the flange on the elbow assembly.FIG. 3-6-2 shows the vent cap 640 assembled to the elbow assembly 680,with the flange 686 on the elbow assembly 680 engaged within the groove662 of the engagement ring 660 of the vent cap 640.

FIGS. 3-7-1 to 3-7-5 show the elbow assembly 680 and mask vent 640 of

FIGS. 3-6-1 to 3-6-9 provided to a mask system 600 according to anexample of the present technology. The mask system 600 includes a maskframe 610, cushion 620, and forehead support 625, further examples anddetails of such mask system being disclosed in U.S. Pat. No. 7,523,754,which is incorporated herein by reference in its entirety. However, itshould be appreciated that the elbow assembly and mask vent thereof maybe adapted for use with other suitable interface types. The elbowassembly 680 is structured to releasably engage a flange 617 surroundingthe opening in the mask frame 610 of the mask system 600, e.g., with asnap-fit.

FIGS. 3-8-1 and 3-8-2 show an elbow assembly 780 and mask vent 740according to another example of the present technology. In this example,the mask vent is integrally formed (e.g., molded) in one piece with theelbow assembly.

As illustrated, the elbow assembly 780 includes a first end 781structured to releasably engage with an opening in a mask frame and asecond end 782 structured to releasably engage with an air delivery tube798. In this example, the interior of the elbow assembly is providedwithout a baffle. The mask vent provides inlet portion 744 with arcuateor angled side wall 745 to guide exhaust gas exiting from the first end781 towards the vent, vent portion 746 including interior wall 749 withthe plurality of vent holes 742, and outlet portion 748 including sidewall 750 to diffuse vent flow and ensure gas is vented in a directionaway from the mask system and the patient 1000 as described above. Asillustrated, the side wall 750 includes a semi-circular configurationthat overlaps with the cuff 799 of the air delivery tube 798 toestablish the outlet portion 748 that surrounds the vent holes 742.

FIGS. 3-9-1 and 3-9-2 show an elbow assembly 880 and mask vent 840according to another example of the present technology. In this example,the vent holes 842 are provided to side wall 845 of the elbow assembly880, and the outlet portion 848 including side wall 850 that surroundsthe vent holes 842 is provided as a separate cover piece that is formedseparately and attached to the side wall 845 of the elbow assembly 880,e.g., with a snap fit. In an example, the cover piece is provided as aretrofit to an existing elbow assembly. However, it should beappreciated that the cover piece may be integrated or integrally formedin one-piece, e.g., co-molded, with the elbow assembly.

In the illustrated example, the cover piece includes semi-circular armsor wings 852 extending from lateral sides of the side wall 850. The armsor wings 852 are resiliently flexible and structured to wrap around theperimeter of the elbow assembly to secure the cover piece in position.

FIGS. 3-10-1 and 3-10-2 show an elbow assembly 980 and mask vent 940according to another example of the present technology. In this example,the mask vent is integrally formed (e.g., molded) in one piece with theelbow assembly.

As illustrated, the elbow assembly 980 includes a first end 981structured to releasably engage with an opening in a mask frame and asecond end 982 structured to releasably engage with an air deliverytube. In this example, the interior of the elbow assembly is providedwithout a baffle. The mask vent provides inlet portion 944 with arcuateor angled side wall 945 to guide exhaust gas exiting from the first end981 towards the vent, vent portion 946 including interior wall 949 withthe plurality of vent holes 942, and outlet portion 948 including sidewall 950 to diffuse vent flow and ensure gas is vented in a directionaway from the mask system and the patient 1000 as described above. Asillustrated, the side wall 950 is spaced from the second end 982 bysupport wall 983.

FIGS. 3-11-1 and 3-11-2 show an elbow assembly 1080 and mask vent 1040according to another example of the present technology. In this example,the mask vent is integrally formed (e.g., molded) in one piece with theelbow assembly.

As illustrated, the elbow assembly 1080 includes a first end 1081structured to releasably engage with an opening in a mask frame and asecond end 1082 structured to releasably engage with an air deliverytube. In this example, the axes of the vent holes 1042 and alongitudinal axis a1 of the outlet portion 1048 are aligned or parallelwith a longitudinal axis a2 of the first end 1081 of the elbow assembly.As illustrated, the side wall 1050 of the outlet portion 1048 supportsthe vent wall 1049 with the plurality of vent holes 1042 within aninterior of the elbow assembly, and the side wall 1050 overlaps withside walls of the elbow assembly 1080. In an alternative implementation,the side wall 1050 coincides with the side walls of the elbow assembly1080. In other words, the side walls of the elbow assembly 1080 alsoserve as the side wall 1050 of the outlet portion 1048.

FIGS. 3-12-1 and 3-12-2 show an elbow assembly 1180 and mask vent 1140according to another example of the present technology. In this example,the mask vent is integrally formed (e.g., molded) in one piece with theelbow assembly.

As illustrated, the elbow assembly 1180 includes a first end 1181structured to releasably engage with an opening in a mask frame and asecond end 1182 structured to releasably engage with an air deliverytube. In this example, the mask vent 1140 is provided on lateral sidesof the elbow assembly. Each mask vent 1140 includes a recessedconfiguration with the side wall 1150 of the outlet portion 1148supporting the vent wall 1149 with the plurality of vent holes 1142within an interior of the elbow assembly.

FIGS. 3-13-1 and 3-13-2 show an elbow assembly 1280 and mask vent 1240according to another example of the present technology. In this example,the mask vent is integrally formed (e.g., molded) in one piece with theelbow assembly.

Similar to the example of FIGS. 3-11-1 and 3-11-2, the axes of the ventholes 1242 and a longitudinal axis a1 of the outlet portion 1248 arealigned or parallel with a longitudinal axis a2 of the first end 1281 ofthe elbow assembly, and the side wall 1250 supports the vent wall 1249with the plurality of vent holes 1242 within an interior of the elbowassembly. In this example, the side wall 1250 extends further into theinterior of the elbow assembly so as to define at least a portion of abaffle wall that separates the intake port and the exhaust port. As afurther benefit of this extension, during inspiration, the Venturieffect results in a relatively low pressure zone around the ventingholes and thus reduces the venting flow through the vent 1240 duringinspiration. Conversely, during expiration, the Venturi effect resultsin enhanced gas washout.

8.3.5 Decoupling Structure(s)

In one form the patient interface 3000 includes at least one decouplingstructure, for example a swivel or a ball and socket.

8.3.6 Connection Port 3600

Connection port 3600 allows for connection to the air circuit.

8.3.7 Forehead Support 3700

In one form, the patient interface 3000 includes a forehead support3700, e.g. see FIG. 3-7-5.

8.3.8 Anti-Asphyxia Valve

In one form, the patient interface 3000 includes an anti-asphyxia valve.

8.3.9 Ports

In one form of the present technology, a patient interface 3000 includesone or more ports, that allow access to the volume within the plenumchamber 3200. In one form this allows a clinician to supply supplementaloxygen. In one form this allows for the direct measurement of a propertyof gases within the plenum chamber 3200, such as the pressure.

8.4 Pap Device 4000

A preferred PAP device 4000 in accordance with one aspect of the presenttechnology comprises mechanical and pneumatic components 4100,electrical components 4200 and is programmed to execute one or morealgorithms. An exemplary PAP device has an external housing 4010, formedin two parts, an upper portion 4012 of the external housing 4010, and alower portion 4014 of the external housing 4010. In alternative forms,the external housing 4010 may include one or more panel(s) 4015. The PAPdevice 4000 may comprise a chassis 4016 that supports one or moreinternal components of the PAP device 4000. In one form a pneumaticblock 4020 is supported by, or formed as part of the chassis 4016. ThePAP device 4000 may include a handle 4018.

The pneumatic path of the PAP device 4000 may comprise an inlet airfilter 4112, an inlet muffler, a controllable pressure device capable ofsupplying air at positive pressure (e.g., a blower 4142), and an outletmuffler. The pneumatic block 4020 may comprise a portion of thepneumatic path that is located within the external housing 4010.

The PAP device 4000 may have an electrical power supply 4210, and one ormore input devices 4220. Electrical components 4200 may be mounted on asingle Printed Circuit Board Assembly (PCBA) 4202. In an alternativeform, the PAP device 4000 may include more than one PCBA 4202.

8.5 Glossary

For the purposes of the present technology disclosure, in certain formsof the present technology, one or more of the following definitions mayapply. In other forms of the present technology, alternative definitionsmay apply.

8.5.1 General

Air: In certain forms of the present technology, air supplied to apatient may be atmospheric air, and in other forms of the presenttechnology atmospheric air may be supplemented with oxygen.

Continuous Positive Airway Pressure (CPAP): CPAP treatment will be takento mean the application of a supply of air or breathable gas to theentrance to the airways at a pressure that is continuously positive withrespect to atmosphere, and preferably approximately constant through arespiratory cycle of a patient. In some forms, the pressure at theentrance to the airways will vary by a few centimetres of water within asingle respiratory cycle, for example being higher during inhalation andlower during exhalation. In some forms, the pressure at the entrance tothe airways will be slightly higher during exhalation, and slightlylower during inhalation. In some forms, the pressure will vary betweendifferent respiratory cycles of the patient, for example being increasedin response to detection of indications of partial upper airwayobstruction, and decreased in the absence of indications of partialupper airway obstruction.

8.5.2 Aspects of PAP Devices

Air circuit: A conduit or tube constructed and arranged in use todeliver a supply of air or breathable gas between a PAP device and apatient interface. In particular, the air circuit may be in fluidconnection with the outlet of the pneumatic block and the patientinterface. The air circuit may be referred to as air delivery tube. Insome cases there may be separate limbs of the circuit for inhalation andexhalation. In other cases a single limb is used.

APAP: Automatic Positive Airway Pressure. Positive airway pressure thatis continually adjustable between minimum and maximum limits, dependingon the presence or absence of indications of SDB events.

Blower or flow generator: A device that delivers a flow of air at apressure above ambient pressure.

Controller: A device, or portion of a device that adjusts an outputbased on an input. For example one form of controller has a variablethat is under control—the control variable—that constitutes the input tothe device. The output of the device is a function of the current valueof the control variable, and a set point for the variable. Aservo-ventilator may include a controller that has ventilation as aninput, a target ventilation as the set point, and level of pressuresupport as an output. Other forms of input may be one or more of oxygensaturation (SaO₂), partial pressure of carbon dioxide (PCO₂), movement,a signal from a photoplethysmogram, and peak flow. The set point of thecontroller may be one or more of fixed, variable or learned. Forexample, the set point in a ventilator may be a long term average of themeasured ventilation of a patient. Another ventilator may have aventilation set point that changes with time. A pressure controller maybe configured to control a blower or pump to deliver air at a particularpressure.

Therapy: Therapy in the present context may be one or more of positivepressure therapy, oxygen therapy, carbon dioxide therapy, control ofdead space, and the administration of a drug.

Positive Airway Pressure (PAP) device: A device for providing a supplyof air at positive pressure to the airways.

Transducers: A device for converting one form of energy or signal intoanother. A transducer may be a sensor or detector for convertingmechanical energy (such as movement) into an electrical signal. Examplesof transducers include pressure sensors, flow sensors, carbon dioxide(CO₂) sensors, oxygen (O₂) sensors, effort sensors, movement sensors,noise sensors, a plethysmograph, and cameras.

8.5.3 PAP Device Parameters

Flow rate: The instantaneous volume (or mass) of air delivered per unittime. While flow rate and ventilation have the same dimensions of volumeor mass per unit time, flow rate is measured over a much shorter periodof time. Flow may be nominally positive for the inspiratory portion of abreathing cycle of a patient, and hence negative for the expiratoryportion of the breathing cycle of a patient. In some cases, a referenceto flow rate will be a reference to a scalar quantity, namely a quantityhaving magnitude only. In other cases, a reference to flow rate will bea reference to a vector quantity, namely a quantity having bothmagnitude and direction. Flow will be given the symbol Q. Total flow,Qt, is the flow of air leaving the PAP device. Vent flow, Qv, is theflow of air leaving a vent to allow washout of exhaled gases. Leak flow,Ql, is the flow rate of unintentional leak from a patient interfacesystem. Respiratory flow, Qr, is the flow of air that is received intothe patient's respiratory system.

Leak: Preferably, the word leak will be taken to be a flow of air to theambient. Leak may be intentional, for example to allow for the washoutof exhaled CO₂. Leak may be unintentional, for example, as the result ofan incomplete seal between a mask and a patient's face.

Pressure: Force per unit area. Pressure may be measured in a range ofunits, including cmH₂O, g-f/cm², hectopascal. 1 cmH₂O is equal to 1g-f/cm² and is approximately 0.98 hectopascal. In this specification,unless otherwise stated, pressure is given in units of cmH₂O. For nasalCPAP treatment of OSA, a reference to treatment pressure is a referenceto a pressure in the range of about 4-20 cmH₂O, or about 4-30 cmH₂O. Thepressure in the patient interface is given the symbol Pm.

Sound Power: The energy per unit time carried by a sound wave. The soundpower is proportional to the square of sound pressure multiplied by thearea of the wavefront. Sound power is usually given in decibels SWL,that is, decibels relative to a reference power, normally taken as 10⁻¹²watt.

Sound Pressure: The local deviation from ambient pressure at a giventime instant as a result of a sound wave travelling through a medium.Sound pressure is usually given in decibels SPL, that is, decibelsrelative to a reference pressure, normally taken as 20×10⁻⁶ pascal (Pa),considered the threshold of human hearing.

8.5.4 Anatomy of the Respiratory System

Diaphragm: A sheet of muscle that extends across the bottom of the ribcage. The diaphragm separates the thoracic cavity, containing the heart,lungs and ribs, from the abdominal cavity. As the diaphragm contractsthe volume of the thoracic cavity increases and air is drawn into thelungs.

Larynx: The larynx, or voice box houses the vocal folds and connects theinferior part of the pharynx (hypopharynx) with the trachea.

Lungs: The organs of respiration in humans. The conducting zone of thelungs contains the trachea, the bronchi, the bronchioles, and theterminal bronchioles. The respiratory zone contains the respiratorybronchioles, the alveolar ducts, and the alveoli.

Nasal cavity: The nasal cavity (or nasal fossa) is a large air filledspace above and behind the nose in the middle of the face. The nasalcavity is divided in two by a vertical fin called the nasal septum. Onthe sides of the nasal cavity are three horizontal outgrowths callednasal conchae (singular “concha”) or turbinates. To the front of thenasal cavity is the nose, while the back blends, via the choanae, intothe nasopharynx.

Pharynx: The part of the throat situated immediately inferior to (below)the nasal cavity, and superior to the oesophagus and larynx. The pharynxis conventionally divided into three sections: the nasopharynx(epipharynx) (the nasal part of the pharynx), the oropharynx(mesopharynx) (the oral part of the pharynx), and the laryngopharynx(hypopharynx).

8.5.5 Materials

Silicone or Silicone Elastomer: A synthetic rubber. In thisspecification, a reference to silicone is a reference to liquid siliconerubber (LSR) or a compression moulded silicone rubber (CMSR). One formof commercially available LSR is SILASTIC (included in the range ofproducts sold under this trademark), manufactured by Dow Coming. Anothermanufacturer of LSR is Wacker. Unless otherwise specified to thecontrary, a preferred form of LSR has a Shore A (or Type A) indentationhardness in the range of about 35 to about 45 as measured using ASTMD2240.

Polycarbonate: a typically transparent thermoplastic polymer ofBisphenol-A Carbonate.

8.5.6 Aspects of a Patient Interface

Anti-asphyxia valve (AAV): The component or sub-assembly of a masksystem that, by opening to atmosphere in a failsafe manner, reduces therisk of excessive CO₂ rebreathing by a patient.

Elbow: A conduit that directs an axis of flow of air to change directionthrough an angle. In one form, the angle may be approximately 90degrees. In another form, the angle may be less than 90 degrees. Theconduit may have an approximately circular cross-section. In anotherform the conduit may have an oval or rectangular cross-section.

Frame: Frame will be taken to mean a mask structure that bears the loadof tension between two or more points of connection with a headgear. Amask frame may be a non-airtight load bearing structure in the mask.However, some forms of mask frame may also be air-tight.

Headgear: Headgear will be taken to mean a form of positioning andstabilizing structure designed for use on a head. Preferably theheadgear comprises a collection of one or more struts, ties andstiffeners configured to locate and retain a patient interface inposition on a patient's face for delivery of respiratory therapy. Someties are formed of a soft, flexible, elastic material such as alaminated composite of foam and fabric.

Membrane: Membrane will be taken to mean a typically thin element thathas, preferably, substantially no resistance to bending, but hasresistance to being stretched.

Plenum chamber: a mask plenum chamber will be taken to a mean portion ofa patient interface having walls enclosing a volume of space, the volumehaving air therein pressurised above atmospheric pressure in use. Ashell may form part of the walls of a mask plenum chamber. In one form,a region of the patient's face forms one of the walls of the plenumchamber.

Seal: The noun form (“a seal”) will be taken to mean a structure orbarrier that intentionally resists the flow of air through the interfaceof two surfaces. The verb form (“to seal”) will be taken to mean toresist a flow of air.

Shell: A shell will preferably be taken to mean a curved structurehaving bending, tensile and compressive stiffness, for example, aportion of a mask that forms a curved structural wall of the mask.Preferably, compared to its overall dimensions it is relatively thin. Insome forms, a shell may be faceted. Preferably such walls are airtight,although in some forms they may not be airtight.

Stiffener: A stiffener will be taken to mean a structural componentdesigned to increase the bending resistance of another component in atleast one direction.

Strut: A strut will be taken to be a structural component designed toincrease the compression resistance of another component in at least onedirection.

Swivel: (noun) A subassembly of components configured to rotate about acommon axis, preferably independently, preferably under low torque. Inone form, the swivel may be constructed to rotate through an angle of atleast 360 degrees. In another form, the swivel may be constructed torotate through an angle less than 360 degrees. When used in the contextof an air delivery conduit, the sub-assembly of components preferablycomprises a matched pair of cylindrical conduits. Preferably there islittle or no leak flow of air from the swivel in use.

Tie: A tie will be taken to be a structural component designed to resisttension.

Vent: (noun) the structure that allows a deliberate controlled rate leakof air from an interior of the mask, or conduit to ambient air, to allowwashout of exhaled carbon dioxide (CO₂) and supply of oxygen (O₂).

8.5.7 Terms used in Relation to Patient Interface

Curvature (of a surface): A region of a surface having a saddle shape,which curves up in one direction and curves down in a differentdirection, will be said to have a negative curvature. A region of asurface having a dome shape, which curves the same way in two principledirections, will be said to have a positive curvature. A flat surfacewill be taken to have zero curvature.

Floppy: A quality of a material, structure or composite that is thecombination of features of:

-   -   Readily conforming to finger pressure.    -   Unable to retain its shape when caused to support its own        weight.    -   Not rigid.    -   Able to be stretched or bent elastically with little effort.

The quality of being floppy may have an associated direction, hence aparticular material, structure or composite may be floppy in a firstdirection, but stiff or rigid in a second direction, for example asecond direction that is orthogonal to the first direction.

Resilient: Able to deform substantially elastically, and to releasesubstantially all of the energy upon unloading, within a relativelyshort period of time such as 1 second.

Rigid: Not readily deforming to finger pressure, and/or the tensions orloads typically encountered when setting up and maintaining a patientinterface in sealing relationship with an entrance to a patient'sairways.

Semi-rigid: means being sufficiently rigid to not substantially distortunder the effects of mechanical forces typically applied during positiveairway pressure therapy.

8.6 Other Remarks

A portion of the disclosure of this patent document contains materialwhich is subject to copyright protection. The copyright owner has noobjection to the facsimile reproduction by anyone of the patent documentor the patent disclosure, as it appears in the Patent and TrademarkOffice patent file or records, but otherwise reserves all copyrightrights whatsoever.

Unless the context clearly dictates otherwise and where a range ofvalues is provided, it is understood that each intervening value, to thetenth of the unit of the lower limit, between the upper and lower limitof that range, and any other stated or intervening value in that statedrange is encompassed within the technology. The upper and lower limitsof these intervening ranges, which may be independently included in theintervening ranges, are also encompassed within the technology, subjectto any specifically excluded limit in the stated range. Where the statedrange includes one or both of the limits, ranges excluding either orboth of those included limits are also included in the technology.

Furthermore, where a value or values are stated herein as beingimplemented as part of the technology, it is understood that such valuesmay be approximated, unless otherwise stated, and such values may beutilized to any suitable significant digit to the extent that apractical technical implementation may permit or require it.

Unless defined otherwise, all technical and scientific terms used hereinhave the same meaning as commonly understood by one of ordinary skill inthe art to which this technology belongs. Although any methods andmaterials similar or equivalent to those described herein can also beused in the practice or testing of the present technology, a limitednumber of the exemplary methods and materials are described herein.

When a particular material is identified as being preferably used toconstruct a component, obvious alternative materials with similarproperties may be used as a substitute. Furthermore, unless specified tothe contrary, any and all components herein described are understood tobe capable of being manufactured and, as such, may be manufacturedtogether or separately.

It must be noted that as used herein and in the appended claims, thesingular forms “a”, “an”, and “the” include their plural equivalents,unless the context clearly dictates otherwise.

All publications mentioned herein are incorporated by reference todisclose and describe the methods and/or materials which are the subjectof those publications. The publications discussed herein are providedsolely for their disclosure prior to the filing date of the presentapplication. Nothing herein is to be construed as an admission that thepresent technology is not entitled to antedate such publication byvirtue of prior invention. Further, the dates of publication providedmay be different from the actual publication dates, which may need to beindependently confirmed.

Moreover, in interpreting the disclosure, all terms should beinterpreted in the broadest reasonable manner consistent with thecontext. In particular, the terms “comprises” and “comprising” should beinterpreted as referring to elements, components, or steps in anon-exclusive manner, indicating that the referenced elements,components, or steps may be present, or utilized, or combined with otherelements, components, or steps that are not expressly referenced.

The subject headings used in the detailed description are included onlyfor the ease of reference of the reader and should not be used to limitthe subject matter found throughout the disclosure or the claims. Thesubject headings should not be used in construing the scope of theclaims or the claim limitations.

Although the technology herein has been described with reference toparticular embodiments, it is to be understood that these embodimentsare merely illustrative of the principles and applications of thetechnology. In some instances, the terminology and symbols may implyspecific details that are not required to practice the technology. Forexample, although the terms “first” and “second” may be used, unlessotherwise specified, they are not intended to indicate any order but maybe utilised to distinguish between distinct elements. Furthermore,although process steps in the methodologies may be described orillustrated in an order, such an ordering is not required. Those skilledin the art will recognize that such ordering may be modified and/oraspects thereof may be conducted concurrently or even synchronously.

It is therefore to be understood that numerous modifications may be madeto the illustrative embodiments and that other arrangements may bedevised without departing from the spirit and scope of the technology.

8.7 REFERENCE SIGNS LIST

-   100 mask system-   110 mask frame-   112 opening-   115 exterior surface-   120 patient contacting portion-   130 shroud-   132 opening-   134 opening-   140 mask vent-   141 venting area-   142 vent hole-   150 continuous side wall-   241 venting area-   242 vent hole-   250 side wall-   341 venting area-   342 vent hole-   350 side wall-   441 venting area-   442 vent hole-   445 rib-   450 side wall-   540 mask vent-   542 vent hole-   544 inlet portion-   545 side wall-   546 vent portion-   548 outlet portion-   549 interior wall-   550 side wall-   580 elbow assembly-   581 first end-   582 second end-   583 collar-   584 baffle-   590 intake port-   592 exhaust port-   600 mask system-   610 mask frame-   617 flange-   620 cushion-   625 forehead support-   640 vent cap-   642 vent hole-   643 main body-   644 inlet portion-   645 side wall-   646 vent portion-   647 support wall-   647.1 wall portion-   647.2 wall portion-   648 outlet portion-   649 interior wall-   650 side wall-   660 engagement ring-   661 groove-   662 groove-   664 entry opening-   680 elbow assembly-   681 first end-   682 second end-   684 baffle-   686 flange-   687 annular wall-   690 intake port-   692 exhaust port-   740 mask vent-   742 vent hole-   744 inlet portion-   745 side wall-   746 vent portion-   748 outlet portion-   749 interior wall-   750 side wall-   780 elbow assembly-   781 first end-   782 second end-   798 air delivery tube-   799 cuff-   840 mask vent-   842 vent hole-   845 side wall-   848 outlet portion-   850 side wall-   852 wing-   880 elbow assembly-   940 mask vent-   942 vent hole-   945 side wall-   946 vent portion-   948 outlet portion-   949 interior wall-   950 side wall-   980 elbow assembly-   981 first end-   982 second end-   983 support wall-   1000 patient-   1040 mask vent-   1042 vent hole-   1048 outlet portion-   1049 vent wall-   1050 side wall-   1080 elbow assembly-   1081 first end-   1082 second end-   1100 partner-   1140 mask vent-   1142 vent hole-   1148 outlet portion-   1149 vent wall-   1150 side wall-   1180 elbow assembly-   1181 first end-   1182 second end-   1240 vent-   1242 vent hole-   1248 outlet portion-   1249 vent wall-   1250 side wall-   1280 elbow assembly-   1281 first end-   3000 patient interface-   3100 seal-forming structure-   3110 sealing flange-   3120 support flange-   3200 plenum chamber-   3400 vent-   3600 connection port-   3700 forehead support-   4000 PAP device-   4010 external housing-   4012 upper portion-   4014 portion-   4015 panel-   4016 chassis-   4018 handle-   4020 pneumatic block-   4100 pneumatic component-   4112 inlet air filter-   4142 blower-   4170 air circuit-   4200 electrical component-   4202 board assembly-   4210 electrical power supply-   4220 input device-   5000 humidifier

The invention claimed is:
 1. A mask system to deliver of a flow of airat a positive pressure with respect to ambient air pressure to anentrance to the patient's airways including at least the entrance of apatient's nares to ameliorate sleep disordered breathing, the masksystem comprising: a frame, wherein the frame includes an openingstructured to receive the flow of air at the positive pressure forbreathing by a patient; a cushion provided to the frame, the cushionconstructed and arranged to seal with a region of the patient's facesurrounding at least the entrance to the patient's nares, wherein theframe and the cushion form a plenum chamber pressurizable to thepositive pressure above ambient air pressure; and a mask ventconstructed and arranged to allow exhaust of gases exhaled by thepatient from an interior of the plenum chamber to ambient, the mask ventincluding: a plurality of vent holes each extending through a thicknessof the frame and each including a vent exit, a continuous side wallstructured to surround the plurality of vent exits formed by theplurality of vent holes, and a plurality of interior ribs arrangedwithin the continuous side wall, wherein the continuous side wallincludes a side exterior surface and an opposite interior surface,wherein the continuous sidewall has a height extending from an exteriorsurface of the frame to a top exterior surface of the continuoussidewall, the top exterior surface is formed between the side exteriorsurface and the interior surface, the top exterior surface surrounds anopening, the opening allowing air to flow from the plurality of ventholes to an outside of the continuous sidewall, wherein each of theplurality of interior ribs extends from the interior surface of thecontinuous side wall and the plurality of interior ribs extend betweenthe plurality of vent holes and the top exterior surface of thecontinuous sidewall, the plurality of interior ribs do not extend pastthe entire top exterior surface to the outside of the continuoussidewall, and wherein the plurality of interior ribs are spaced apartfrom one another around a perimeter of the continuous side wall to atleast partially divide exhaust vent airflow exiting the plurality ofvent exits formed by the plurality of vent holes.
 2. The mask systemaccording to claim 1, wherein the continuous side wall and the pluralityof interior ribs are structured and arranged such that the exhaust ventairflow encounters the continuous side wall and the plurality ofinterior ribs upon exiting the plurality of vent exits formed by theplurality of vent holes.
 3. The mask system according to claim 1,wherein each rib of the plurality of interior ribs is spaced apart fromone another with an end of each rib of the plurality of interior ribsbeing a free end and is a farthest end of the each rib of the pluralityof interior ribs relative to the interior surface.
 4. The mask systemaccording to claim 1, wherein each of the plurality of interior ribs isstructured and arranged to extend from the continuous side wall and atleast partially into an interior formed by the continuous side wall. 5.The mask system according to claim 1, wherein each of the plurality ofinterior ribs is structured and arranged to project from the exteriorsurface of the frame outwards from the vent exits of the vent holes andaway from the interior of the plenum chamber.
 6. The mask systemaccording to claim 1, wherein the continuous side wall includes a heightthat is larger than a length of each of the plurality of vent holes. 7.The mask system according to claim 1, wherein each of the plurality ofvent holes includes a part conic shape.
 8. The mask system according toclaim 1, wherein each of the plurality of vent holes includes acylindrical shape.
 9. The mask system according to claim 1, wherein theplurality of vent holes is in a range of 5 holes to 20 holes.
 10. Themask system according to claim 1, wherein the continuous side wall andeach of the plurality of interior ribs are structured and arranged toproject outwards from the exterior surface of the frame in a directionof the exhaust vent airflow.
 11. The mask system according to claim 1,wherein the plurality of vent holes are arranged to provide a ventingarea, and the continuous side wall is structured to surround the entireventing area.
 12. The mask system according to claim 1, wherein each ofthe plurality of interior ribs forms a trailing edge downstream from theexterior surface of the frame, and each of the plurality of interiorribs includes a height extending from the exterior surface of the frameto the trailing edge of each of the plurality of interior ribs, and theheight of each of the plurality of interior ribs is less than the heightof the continuous side wall.
 13. The mask system according to claim 1,wherein the plurality of interior ribs includes a first rib that isaxially aligned with a second rib.
 14. The mask system according toclaim 1, further comprising a connector provided to the frame andadapted to connect the frame to an air delivery tube that deliversbreathable gas to the patient.
 15. The mask system according to claim 1,further comprising a pair of rigidizer arms, wherein each rigidizer armof the pair of rigidizer arms extends from a respective side of theframe and adapted to connect to a respective one of a pair of sidestraps of headgear, and wherein the mask vent is arranged between thepair of rigidizer arms.
 16. The mask system according to claim 1,further comprising a shroud provided to the frame, wherein the shroudincludes a wall arranged outside the plenum chamber.
 17. The mask systemaccording to claim 16, wherein the shroud includes an edge that forms anopening to allow exhaust vent airflow from the mask vent.
 18. The masksystem according to claim 1, wherein the continuous side wall and theplurality of interior ribs are structured and arranged such that theexhaust vent airflow encounters the continuous side wall and theplurality of interior ribs upon exiting the plurality of vent exitsformed by the plurality of vent holes, wherein each rib of the pluralityof interior ribs is spaced apart from one another with an end of eachrib of the plurality of interior ribs being a free end and is a farthestend of the each rib of the plurality of interior ribs relative to theinterior surface, wherein each of the plurality of interior ribs isstructured and arranged to extend from the continuous side wall and atleast partially into an interior formed by the continuous side wall,wherein each of the plurality of interior ribs is structured andarranged to project from the exterior surface of the frame outwards fromthe vent exits of the vent holes and away from the interior of theplenum chamber, wherein the continuous side wall includes a height thatis larger than a length of each of the plurality of vent holes, whereinthe plurality of vent holes is in a range of 5 holes to 20 holes,wherein the continuous side wall and each of the plurality of interiorribs are structured and arranged to project outwards from the exteriorsurface of the frame in a direction of the exhaust vent airflow, andwherein the plurality of vent holes are arranged to provide a ventingarea, and the continuous side wall is structured to surround the entireventing area.
 19. The mask system according to claim 18, wherein each ofthe plurality of interior ribs forms a trailing edge downstream from theexterior surface of the frame, and each of the plurality of interiorribs includes a height extending from the exterior surface of the frameto the trailing edge of each of the plurality of interior ribs, and theheight of each of the plurality of interior ribs is less than the heightof the continuous side wall, and wherein the plurality of interior ribsincludes a first rib that is axially aligned with a second rib.
 20. Themask system according to claim 19, further comprising a pair ofrigidizer arms, wherein each rigidizer arm of the pair of rigidizer armsextends from a respective side of the frame and adapted to connect to arespective one of a pair of side straps of headgear, and wherein themask vent is arranged between the pair of rigidizer arms, furthercomprising a shroud provided to the frame, wherein the shroud includes awall arranged outside the plenum chamber, and wherein the shroudincludes an edge that forms an opening to allow exhaust vent airflowfrom the mask vent.